Influence of procedure variables on C-Mn-Ni-Mo ANSI/AWS A5.29-98 E111T5-K3 metal cored wire ferritic all-weld metal

摘要

The objective of this work was to study the effect that the utilization of different shielding gases (CO_2 and a mixture 80 percent Ar / 20 percent CO_2), welding position (flat and vertical up), arc energy and number of passes per layer (2 and 3) have on the allweld metal microstructure and mechanical properties from an ANSI/AWS A5.29-98 E111T5-K3/K3M 1.2 mm diameter metal cored wire. Hardness, tensile and impact tests were used to assess the mechanical properties and quantitative metallographic analysis were performed to identify the resulting microstructures. ANSI/AWS A5.29-98 E111T5-K3/K3M tensile property requirements were satisfied under Ar/CO_2 shielding and E111T5-K3/K3M chemical composition specification was met in all conditions, except for Mo requirements, with maximum value exceeding those of the standard. E111T5-K3/K3M toughness requirements were comfortably satisfied under both gas types, but significant variations were found with different welding procedures. These variations have been rationalized in terms of the microstructure and chemical composition of the weld deposits. The results obtained in this work showed that, as in the case of SMAW electrodes of the type ANSI/AWS A5.5-96 E10018/11018/ 12018-M types, depositing C-Mn-Ni-Mo or C-Mn-Ni-Mo-Cr alloyed ferritic weld metal, the main difficulty resides in obtaining adequate tensile strength values rather than in satisfying toughness requirements that can be met almost under any welding condition, within the requirements of the appropriate standard.